diff --git a/jellyfish/peer_notifications.proto b/jellyfish/peer_notifications.proto
index ffcc17e..269a018 100644
--- a/jellyfish/peer_notifications.proto
+++ b/jellyfish/peer_notifications.proto
@@ -2,13 +2,17 @@ syntax = "proto3";
 
 package jellyfish;
 
+// Defines any type of message sent between JF and a peer
 message PeerMessage {
+  // Response sent by JF, confirming successfull authentication
   message Authenticated {}
 
+  // Request sent by peer, to authenticate to JF server
   message AuthRequest {
     string token = 1;
   }
 
+  // Any type of WebRTC messages passed betweend JF and peer
   message MediaEvent {
     string data = 1;
   }
diff --git a/jellyfish/server_notifications.proto b/jellyfish/server_notifications.proto
index 1c0c925..f8e200d 100644
--- a/jellyfish/server_notifications.proto
+++ b/jellyfish/server_notifications.proto
@@ -2,76 +2,144 @@ syntax = "proto3";
 
 package jellyfish;
 
+// Defines any type of message passed between JF and server client
 message ServerMessage {
+  // Notification sent when a room crashes
   message RoomCrashed {
     string room_id = 1;
   }
 
+  // Notification sent when a peer connects
   message PeerConnected {
     string room_id = 1;
     string peer_id = 2;
   }
 
+  // Notification sent when a peer disconnects from JF
   message PeerDisconnected {
     string room_id = 1;
     string peer_id = 2;
   }
 
+  // Notification sent when a peer crashes
   message PeerCrashed {
     string room_id = 1;
     string peer_id = 2;
   }
 
+  // Notification sent when a component crashes
   message ComponentCrashed {
     string room_id = 1;
     string component_id = 2;
   }
 
+  // Response sent by JF, confirming successfull authentication
   message Authenticated {}
 
+  // Request sent by client, to authenticate to JF server
   message AuthRequest {
     string token = 1;
   }
 
+  // Defines message groups for which client can subscribe
   enum EventType {
     EVENT_TYPE_UNSPECIFIED = 0;
     EVENT_TYPE_SERVER_NOTIFICATION = 1;
     EVENT_TYPE_METRICS = 2;
   }
 
+  // Request sent by client to subsribe for certain message type
   message SubscribeRequest {
     EventType event_type = 1;
   }
 
+  // Response sent by JF, confirming subscription for message type
   message SubscribeResponse {
     EventType event_type = 1;
   }
 
+  // Notification sent when a room is created
   message RoomCreated {
     string room_id = 1;
   }
 
+  // Notification sent when a room is deleted
   message RoomDeleted {
     string room_id = 1;
   }
 
+  // Message containing WebRTC metrics from JF
   message MetricsReport {
     string metrics = 1;
   }
 
+  // Notification sent when the HLS stream becomes available in a room
   message HlsPlayable {
     string room_id = 1;
     string component_id = 2;
   }
 
+  // Notification sent when the HLS recording is successfully uploded to AWS S3
   message HlsUploaded {
     string room_id = 1;
   }
 
+  // Notification sent when the upload of HLS recording to AWS S3 fails
   message HlsUploadCrashed {
     string room_id = 1;
   }
 
+  // Notification sent when peer updates its metadata
+  message PeerMetadataUpdated {
+    string room_id = 1;
+    string peer_id = 2;
+    string metadata = 3;
+  }
+
+  // Defines types of tracks being published by peers and component
+  enum TrackType {
+    TRACK_TYPE_UNSPECIFIED = 0;
+    TRACK_TYPE_VIDEO = 1;
+    TRACK_TYPE_AUDIO = 2;
+  }
+
+  // Describes a media track
+  message Track {
+    string id = 1;
+    TrackType type = 2;
+    string metadata = 3;
+  }
+
+  // Notification sent when peer or component adds new track
+  message TrackAdded {
+    string room_id = 1;
+    oneof endpoint_info {
+      string peer_id = 2;
+      string component_id = 3;
+    }
+    Track track = 4;
+  }
+
+  // Notification sent when a track is removed
+  message TrackRemoved {
+    string room_id = 1;
+    oneof endpoint_info {
+      string peer_id = 2;
+      string component_id = 3;
+    }
+    Track track = 4;
+  }
+
+  // Notification sent when metadata of a multimedia track is updated
+  message TrackMetadataUpdated {
+    string room_id = 1;
+    oneof endpoint_info {
+      string peer_id = 2;
+      string component_id = 3;
+    }
+    Track track = 4;
+  }
+
   oneof content {
     RoomCrashed room_crashed = 1;
     PeerConnected peer_connected = 2;
@@ -88,5 +156,9 @@ message ServerMessage {
     HlsPlayable hls_playable = 13;
     HlsUploaded hls_uploaded = 14;
     HlsUploadCrashed hls_upload_crashed = 15;
+    PeerMetadataUpdated peer_metadata_updated = 16;
+    TrackAdded track_added = 17;
+    TrackRemoved track_removed = 18;
+    TrackMetadataUpdated track_metadata_updated = 19;
   }
 }